That is the exact design I used for my hand throttle. Except I did not add the bracket on the gas pedal; I slotted the existing cable mount point and allowed the hand throttle cable to 'slide' as you press the gas. Then when you operate the hand throttle, your pedal goes down a bit.

Hey Brian, you are a hard man to get ahold of. You don't get PMs and I couldn't leave a voice mail! About your 4.88s...